Cooling method and apparatus for metal working



March 22, 1960 J. A. PAASCHE 2,929,566

COOLING METHOD AND APPARATUS FOR METAL WORKING Filed March 3, 1955 5 Sheets-Sheet l March 22, 1960 J. A. PAASCHE 2,929,566

COOLING METHOD AND APPARATUS FOR METAL WORKING Filed March 3, 1955 5 Sheets-Sheet 2 6 J66 5 .168 55 J78 J55 J54 March 22, 1960 J. A. PAASCHE COOLING METHOD AND APPARATUS FOR METAL WORKING 5 Sheets-Sheet 3 Filed March 3, 1955 March 22, 1960 J. A. PAASCHE 2,929,566

COOLING METHOD AND APPARATUS FOR METAL WORKING Filed March 3, 1955 5 Sheets-Sheet 4 INVENTOR.

76326 @Paasck %?0 w March 22, 1960 J. A. PAASCHE 2,929,566

COOLING METHOD AND APPARATUS FOR METAL WORKING Filed March 5, 1955 5 Sheets-Sheet 5 IN VEN TOR.

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2,929,555 Patented Mar. 22, 1960 iZDULlNG METHGD AND APPARATUS FOR METAL WORKING Jens A. Paasche, Chicago, 111., assignor, by rnesne assignments, to The Paasche Company Appiicntion March 3, 1955, Serial No. 491,977

2 Ii-aims. {C1, 239-273) The present invention relates to a novel apparatus for use in connection with substantially all types of metal working machines, power saws and grinding machines for cooling the tools, saw blades and grinding wheels as well as the work.

It has long been the general practice in many metal forming or cutting operations to direct a stream of cooling liquid or cooling oil over the work and tool to flood the area around the point of contact between the tool and work for cooling purposes. Such prior systems are subject to several disadvantages and, in addition, frequently fail to provide the most efiective cooling action. For example, in many installations using prior cooling systems, the liquid coolant is continuously splashed over the machine, the operator and the surrounding floor area so that large amounts of the coolant are lost and considerable labor must be expended to keep the machine and floor clean. Furthermore, some means must be provided for reclaiming the cooling liquid which is normally collected along with scrap and chips from the workpiece, which reclaiming requires the use of considerable apparams and labor and seldom can be carried out sufiiciently to prevent the loss of a substantial amount of cooling liquid.

An important object of the present invention is to provide a novel apparatus to be used in connection with metal working or cutting machines for cooling the workpiece and cutting tool more efiiciently so as to permit substantial increases in the rate of metal working and to prolong the life of the metal working tool, whereby workpieces may be more rapidly and economically produced.

A more specific object of the present invention is to provide a novel apparatus of the above described type which utilizes relatively small amounts of a cooling liquid so that the loss of cooling liquid for a given operation is reduced.

Still another object of the present invention is to provide a novel apparatus of the above described type which delivers relatively small amounts of cooling liquid in atomized form in a manner so that the necessity for re claiming the liquid is eliminated and so that the metal working machine, the operator, and the surrounding fioor area will not become covered by the liquid whereby cleaning costs may be substantially reduced.

Still another object of the present invention is to provide a novel apparatus or unit of the above described type which is substantially self-contained and which may be easily mounted on various standard metal working machines such as turret lathes, automatic screw machines, milling machines, planers, drill and tapping machines, power saws, grinding machines and the like.

Another more specific object of the present invention is to provide a novel apparatus or self contained unit of the above described type which will automatically start and stop delivery of coolant upon starting and stopping of the metal working machine.

Other objects and advantages of the present invention will become apparent from the following description and the accompanying drawings wherein:

Fig. l is an elevational view showing a unit embodying the principles of this invention mounted on a turret lathe;

Fig. 2 is a fragmentary perspective view of a portion of the assembly shown in Fig. 1;

Fig. 3 is an enlarged fragmentary sectional view taken along line 3-3 in Fig. i;

Fig. 4 is a longitudinal sectional view of a novel atomizer gun utilized in the apparatus of this invention;

Fig. 5 is a cross sectional view taken along line 5-5 in Fig. 4;

Fig. 6 is a cross sectional view taken along line 6-6 in Fig. 4;

Fig. 7 is a cross sectional view taken along line 7-7 in Fig. 4;

Fig. 8 is a perspective view showing one form of the jet nozzle tip adapted to be connected with the atomizer Fig. 9 is an exploded perspective view showing another jet nozzle tip assembly;

Figs. 10, 11 and 12 are longitudinal sectional views of various jet nozzle tips formed in accordance with the present invention;

Fig. 13 is an enlarged sectional view showing a portion of the cooling liquid supply reservoir and the assembiy for distributing cooling liquid and compressed air to a plurality of autornatic atomizing guns;

Fig. 14 is an enlarged r'ragmentary sectional view showing the manner in which a flexible plastic hose is connected with the distributorassembly;

Fig. 15 is a fragmentary sectional view taken along line 1515 in Fig. 13;

Fig. 16 is a fragmentary perspective view showing a unit embodying the principles of this invention mounted on a drill press;

Fig. 17 is a fragmentary perspective view showing another unit embodying the principles of this invention mounted on a milling machine;

Fig. 18 is a fragmentary sectional view showing how coolant may be directed by the apparatus of this invention against a tapping tool;

Fig. 19 is a perspective view showing the jet nozzle tip and the shape of the atomized jet delivered thereby;

Fig. 20 is a fragmentary perspective view showing another jet nozzle tip and a shape of the atomized jet delivered thereby; and

Figs. 21, 22 and 23 show the manner of impinging jets of atomized coolant and compressed air against the work and tools in various installations.

Referring now more specifically to the drawings wherein like parts are designated by the same numerals throughout the various figures, a cooling unit 30 embodying the principles of this invention is shown in Figs. 1 and 2 mounted on a turret lathe 32 of known construction; As will be understood, the turret lathe includes a rotatable chuck 34 adapted to carry a workpiece 36, an indexing turret 38 carrying a plurality of tools 40, and an operating handle 42 which is actuated back and'forth upon starting and stopping of the machine. The cooling apparatus or unit 30 includes a reservoir 44 for a supply of liquid coolant, an air pressure regulator 46 adapted to be connected with any suitable source of air under pressure, not shown, by a hose 4%, an air control valve 56, one or more atomizing jet guns 52 and 53, and means 54 for distributing the liquid coolant and air under pressure to the jet cool guns.

The reservoir 44 is in the form of an inverted bottle having a removable cover 56 to permit filling thereof. The bottle is formed from a clear or translucent material sai thaflggoperator may readily observe the supply of cooling liquid containedtherein. Preferably, the bottle is formed from a plastic material so as to eliminate any.

liquid passageways 6 8 which intersect its central bore 7% Into. each of t'he'se downwardly inclined passageways, there is threaded a nipple 72' of shut-ofivalves 74'and 75, each of which shut-ofi valves is connected with a separateatomizing gun as; will be described below. In order to prevent any contaminating particles in theliquid coolant from passing to and clogging the atomizing' guns, adomeshaped filter 76 is provided, This filter is mounted on a an annular seat '73 formed in the upper. end of the threaded shank portion 62 and is retained in position by a snap ring or the like 80. While the member all is disclosed asbeing formed for distributing cooling liquid to a 'pair of atomizing guns, it is contemplated that this member may beformed and means may be provided for distributing liquid to a different number of atomizing guns.

Thedistributor assembly 54 also includes a member 32 for directing air under pressure to a plurality of atomizing guns, which member has a solidnipple 84 threaded into an aperture 86 in the lowerend of the member 69. In addition, the member 82 is provided with a-threaded aperture-88 into, which the upper end ofa'support or standard 90 may be inserted for mounting both the reservoir and the distributor assembly. The standard it! is,

in turn, mounted on the machine tool or turret lathe or to any suitable support structure, not shown, adjacent the machine tool. The member 82 is provided with an air passageway 92 into which a fitting 94 on an end of spring 124 to a positionfor" shutting off the air under pressure from the port 120 and'thus, from the distributor assembly and atomizing gun. A swivel lever 126 is pivotally mounted for engaging an end of the valve stem 122, which lever carriesa roller 123, engageable with an end 1300f the operating handle 42 of the machine tool. The arrangement is such that when the operating handle 42 is shifted upon starting of the machine tool, the lever 126 is pivoted against the valve stem 122 to shift the valve stem to an open' position. Furthermore,

, when the operating handle 42 is shifted back to its original position upon stopping of the machine tool, the spring 124 functions to shift'the valve stem back to theclosed position. Thus, the air under pressure is automatically supplied to and shut off from the atomizing guns upon starting and stopping of themachine tool.

All .of the guns are identical and/therefore, only the atomizing gun 52,,which is shown in detail in Figs. 4 through 7, need'be described. Theato'mizing gun 52 includes a main body member 132 and a hollowbody' portion134 which is connected to the body member 132 by a fitting 136 threaded into .an aperture 133 and drawn against the body member132 by a nut member 140.; The

body member 132 is provided with a central chambe'r 142 to which the cooling liquid'is directed through a lateral passageway 144 formed'in a nipple 146; 'An internalnozzle 148 is threaded into the end of the body 7 member .132 and communicates with the chamber142,

7 below.

an air hose 96 is threaded. The'airhose 96fis also connected with the control valve 59, as will'be' described below. In the particular embodiment illustrated the member 82 is also provided with 'a pair-of circumferentially spaced passageways 93 and 101} which intersect the passageway $2.

atomizing guns.

of atomizing guns.

The air pressure regulator 46 and the control valve 56 are preferably mounted together in a single assembly and may be supported by any suitable means such as a bracket secured to the side of a machine tool. The air pressure regulator 46 may be of any known construction and, therefore, .need not be described in detail, and it sufiices to state that the air. pressure regulator is of the type which may be adjusted so as to reduce the pressure ofthe air supplied thereto through the line :48 any desiredarnount. .For use in the apparatus of the present invention thepressureyregulator 46 will usually be adjusted so that airis' directed therefrom through a conduit 112 to the control valve-at pressures betweenabout 30 to 60 p,s.i. .Normally the lower of these pressures are preferred to prevent waste ,of air and coolant, but when hard stock is ,Air under pressure is supplied to a hollow nipple 154 by means described below and passes through a port 156 intoj a chamber 158 within the hollow body portion 134. A plurality of passageways 160 is formed in the fitting 136 for directing the air under pressure from the chamber 158 to an annular chamber 162 from where the air passes th rou'gh a plurality of'passageways 164 which are shown in Figs. 4 and 6. An external'nozzle 166 issecured to the end of thebody member 132 by a nut member'165, and the air passes from the passageway 164 into an annular chamber 170 providedbetween the nozzle 166 and the end of the body memberf132. The nozzle 166 has a tip portion 172 having a restricted orifice therein which is slightly larger than the tip portion of the nozzle 148, and, as shown in Figs. 4 and'S, the nozzle 166 is provided with a plurality of passageways 176 connecting the chamher 170 and the restricted orifice 174. An elongated nozzle tip 178 is threaded ontojthe tip' of the nozzle 166 for directing the sprayof air and coolant to a point of dischargc adjacent the work[. As shown in Figs. 4 and 10,

the tip of the nozzle 148 terminates well within the aperture of the nozzle tip 172, and the elongated nozzle tip 178 has a central passageway 180 with a diameter less than the diam'eter of the aperture 174 and a restricted discharge orifice 182. With this novel arrangement the liquid coolant is broken up into small particles as itenters the relatively large aperture 174 from the restricted orifice so that a highly concentrated air coolant mixture is being cut so that a large amount of heat is generated,

it will be-necessary to use higher pressuresin this range.

As shown best in Fig. 3, the control valveiSG includes a body 114 having a central bore or air passageway 116 withtheconduit'112 and the air hose 96 through suitable coupling devices. A valve stem 1122 is slidably disposed in the bore 116 andis normally' resiliently urged bye formed.

7 it hasbeen found that by-directing an expanding jet many workpieces are cooled to such an extent that they may be immediately picked up in the hand of the operator so that handling of such workpieces is greatly facilitated. It should be noted that this very efficient cooling is obtained with small amounts of the fineiy atomized liquid coolant, which amounts may be on the order of one drop per second, whereby savings in the amount of the liquid coolant used may be effected and whereby the coolant actually used is substantially completely absorbed by the workpiece. As the result of this latter factor, the machine, operator, and surrounding floor area are not splattered or covered with the liquid coolant so that a considerable amount of the time and labor formerly expended to maintain the machine and floor clean is saved and costly pumps and machine parts heretofore used to recover the coolant are also eliminated.

The needle valve 152 is connected to or made integral with a stem 184- which extends through packing means 186 and into the hollow body portion 134. A piston assembly 188 is fixed on the valve stem, and a compression spring 199 acts between the piston and a cap 192 threaded onto the hollow body portion for yieldably biasing the needle valve toward the left as viewed in Fig. 4 to close the restricted orifice 150 and stop the flow of cooling liquid. When the above described control valve is actuated to admit air under pressure to the atomizing gun, the air entering the chamber 158 acts against the piston and forces the piston and the needle valve toward the right against the action of the spring 190 so as to open the orifice 150 and permit the flow of cooling liquid. In order to control the rate at which liquid may fiow through the orifice 15%, means is provided for limiting the amount which the needle valve may be opened. This means includes a stop pin 194 threaded to an apertured boss 196 on the cap 192 and having an inner end disposed for engagement with the valve stem 184 to limit movement thereof. A hollow nut-like member 198 is threaded on the stop pin 194 and is locked or jammed against rotation relative to the stop pin by a cap nut 290. Thus, the stop pin 194 may be adjusted axially relative to the valve stem by turning the nut member 198 which, in turn, causes turning of the stop pin. The nut member 198 is knurled or provided with ribs as at 202 to facilitate easy hand turning thereof. A compression spring 204 is provided between the cap 192 and the nut member 198 for locking the nut member and stop pin in any desired adjusted position. A pointer 206 is provided on the nut member 198, which pointer cooperates with numerals or graduations 208 on the periphery of the cap member 192 to indicate the position to which the stop pin 194 is adjusted and, thus, providing micrometer readings of fluid control.

In order to facilitate mounting of the atomizing gun 52 in the desired position with respect to the work, an air pipe section 210 is joined with the air inlet nipple 154 by a swivel connection. As shown best in Fig. 4, the pipe section 210 has a closed end 212 and a laterally extending fitting 214 is secured to the pipe section adjacent the closed end. The fitting has a rounded end 216 adapted to seat against the end of the nipple 154, and a nutmernher 218 is provided for drawing the rounded end of the fitting into sealing engagement with the seat. It will be appreciated that the spray gun may be twisted relative to the pipe section 210 easily after the nut member 213 has been loosened, and after the spray gun has been adjusted to the desired position, the connection between the pipe section in the atomizing gun may again be sealed by tightening the nut. The atomizing gun 54 is mounted on the machine tool in any desired location adjacent the work by means of a support rod 220 and an adjustable clamp 222 gripping both the support rod 220 and the pipe section 210. The atomizing gun 53 is similarly mounted and this mounting need not be described in detail.

The atomizing gun 52 is connected with the distributor assembly 54 by flexible hoses or conduits 224 and 226. More specifically, the conduit 224 extends between the valve assembly 74 and the inlet nipple 146 on the atomizing gun, and the conduit 226 extends between the valve assembly 106 and the air pipe 216. The conduit 224 is preferably made from a clear plastic material so that an operator may readily see that a supply of the liquid coolant is available to the spray gun. This is important since the jet discharged by the gun against the work contains so little of the liquid coolant that it is almost invisible. Coupling assemblies 228 and 230 are provided for connecting the conduit 224 to the valve 74 and nipple 146, respectively, and similar coupling assemblies 232 and 234 are provided for connecting the conduit 226 to the valve 106 and the pipe 210, respectively. In Fig. 14 the coupling assembly 228 is shown in detail to illustrate the manner in which the ends of the flexible plastic conduits are connected with the coupling assemblies in a secure and sealed manner. The coupling assembly 228 includes a fitting 236 which is connected to the valve member 74 by a nut 238. A short tube 240 is connected with the fitting 236 by a nut member 242, and the tube 240 and the fitting are provided with mating surfaces 244 and 246 which provide a seal. The opposite end of the tube 240 is provided with helical screw threads 2 48 of considerable axial extent. It should be noted that the screw threads 248 decrease in height toward the end of the tube 240 and are provided with fiat crests as indicated at 250. This arrangement provides the tube 240 with a tapering end over which the plastic conduit 224 may be easily slipped, and the flattened crests of the end most screw threads eliminate any danger of cutting the plastic conduit. After the end of the plastic conduit has been slipped over the threads on the tube 240, a nut member 252, which has an internal diameter substantially greater than the external diameter of the tube 240, is slipped along the tube 240 and threaded over the end of the plastic conduit to the position shown in Fig. 14. It should be noted that the threads of the nut member adjacent theleading end thereof decrease in height so as to provide the nut member with a flared mouth 254 to facilitate initial application of the nut member over the end of the plastic conduit. It should be also noted that the internal diameter of the nut member is sufficiently small to cause a portion of the teeth 248 on the tube 240 to be embedded in the plastic conduit without cutting entirely through the plastic conduit. Furthermore, since the mouth of the nut member is flared and since the outer endmost threads on the tube 240 are tapered, the axially spaced threads on the tube will dig into the plastic conduit different amounts. With this arrangement a secure connection between the plastic conduit and the tube 240 is insured while at the same time, any danger of leakage developing as a result of cutting of the plastic conduit is eliminated.

In Fig. 16 there is shown a slightly modified form of the novel apparatus or unit of this invention which is similar to the above described apparatus as indicated by the application of identical reference numerals with the suh'ix :1 added to corresponding elements. This embodiment differs in that it includes only a single atomizing gun and in that it is especially adapted for mounting on a drill press. More specifically, the standard a which supports the reservoir and distributor assembly is mounted on the bed 260 of a drill press by any suitable bracket means 262. The standard is mounted adjacent a workpiece 264 which is held by clamping means 266 beneath a drill 268. In order to support the atomizing gun 52a, a rod 270 is adjustably secured to the standard 90a by clamp means 222a having pivotally connected sections 272 and 274, respectively, gripping the standard 90a and the rod 270. Similar adjustable clamp means 276 connects the rod 270 with the pipe section 21012 of the atomizing gun. Since only one spray gun is being used, one of the ting edges.

60a is closed by a plug 278 and one of the lateral passage ways in the: distributor member 82a is closed by a similar plug, not shown. In order to direct the spray generally axially intothe hole being drilled into the workpiece, the elongated nozzle tip 178a has an end portion thereof bent lateral-1y about 45- asshown in Figs. 8 and 16. This modified form of the nozzle is also shown in Fig. 18 wherein it is arranged for directing the spray into an aperture in 'the workpiece 264 which is being finished with a tapping tool'. 280.

17 shows a portion of another unit embodying a modified form of the present invention, which unit is similar .to the above-described structures as indicated by 'th e application of identical reference numerals with the sufiix fb added .to correspondingelements. This e m bodiment is especially adapted for application to a m lling This nozzle tip extension is provided with an elongated passageway 334 which corresponds to theabove described 'passageway180 throug'hlthe nozzle tip 178, and a restricted outlet orifice 336 which corresponds to the above described outlet orifice 182.

'Figs. 21, 22 and'23 show in greater detailhow the V cooling jets should be impinged against the work and tools in various installations. Fig. 22 shows how a nozzle machine 282 for-directing a plurality of sprays along a broad milling cutter 284 acting upon a workpiece 286'. In this embodiment the liquid coolant inlet nipples of the spray gun 52b and 53b are respectively connected by coupling devices 288 and 290 to a distributing member 292, which distributing member is, in turn, connected by acoupling device 294 .with one end of a pipe section 296. The opposite end of the pipe section 296 is connected to the flexible hose 224b by a coupling device 298. In addition, the pipe section 296 is utilized for supporting the atomizing guns and, more particularly, this pipe section I is connected by adjustable clamp means 390 similar to the above described adjustableclamp means to a horizontal portion of a support rod 302 mounted on the mill- 7 ing machine; With this arrangement, it will be appreciated that atomizing guns may be adjusted horizontally, vertically and longitudinally relative to the milling cutter. In this embodiment, the air conduit 22611 is connected with a distributor member 304 by a coupling device 306,

which distributor member is, in turn, connectedwith the airinlet nipples of the spray guns. More specifically, one 1 the milling cutter" and the workpiece, the elongated nozzle tips 178? are formed with a wide flat discharge orifice i825 as shown best in Figs. 12 and 20. v

, In some installationsit may be possible to arrange the spray guns so that the discharge end of the elongated nozzle tip 178 or the coresponding above described elongated nozzle tips will be close enough to the work, and in such cases, extensionnozzle tips of the type shown in Figs..9 and 11 may be provided. More specifically, in Fig, 9, a tip extension 320 is shownwhichhas an enlarged tapered bore portion 322 so that it may be slipped over and jammed on a tapered end portion 324 of the nozzle tip 178. The tip extension 326 also is provided witha section 326 having an external polygonal shape to facilitate turning of the tip extension and removal thereof from the nozzle tip 178. This polygonal section is disposed between the ends of the tip extension to facilitate machining of the extension. The particular nozzle tip extension shown in Fig. 9 is provided with a 'relativel'y wide and flat discharge orifice 328 similar to tip 178a should be arranged to direct a jet 240 against a drill 242 and into the aperture in a workpiece 244. Fig. 22 shows an. installation wherein a workpiece 246 is to be acted upon a drill 248, a forming tool 250, and a cutting tool 252, and further shows how nozzle tips 1'78, 178:; and 178b should be arranged to impinge jets 254, 256 and 258against the tools and workpiece. Fig. 23 shows another installation wherein a workpiece is to be acted upon by a drill 26t),a forming tool 262, and a cutting tool 264, and wherein nozzle tips 173 and 178a are positioned to direct jets 266 and 268 against the work and tools. I I

The above described novelcooling apparatus or unit may be mounted and operated as follows. The reservoir and distributor assembly are mounted on or adjacent the machine tool and above the cutting station as shown in Fig. 1 so that the cooling liquid will be fed to the spray guns by gravity. The air control valve is mounted at any convenient location so that they will be actuated by the machine operating handle in the manner described above. Then the atomizing guns are mounted and adjusted so that the discharge ends of the nozzle tips or the tip extensions are locatedat a distance of one-half to two inches from the cutting edge of the tool. Then the air pressure regulator is' adjusted so that a gauge reading of between 30 and 60 psi. will be obtained; In addition,

the needle valve control on each spray gun is adjusted to From the above description it is seen that the present invention has provided a novel apparatus or unit which is capable of fully satisfying the objects heretofore set forth. More specifically, it is seen that the present invention has provided aunit which may be easily mounted on various machine tools and adjusted to fill the require- I mentsof the particular work 'forming'operationi It should be noted that while the present apparatus has been primarilydescribed in connection with the use on machines utilizing cutting tools and the like, it isalso useful with othenmachine' tools, power saws, grinding thermore, it will be appreciated that the problems of the above described orifice. 1821; so that it is particularly adapted for use with tools having relatively broad out- Also, this particulartip extension is shown as having an angularly bent/end portion similar to the angularly bent end portion of the above described nozzle tip 178a, but it is understood that the tip extension 320 [may also .be formed straight. For example, in Fig. 11, thereiis shown a straight nozzle tip extension 330 hav-' ing an enlarged bore portion 332 so that it is adapted to be'assernbled with the above described nozzle tip 178.

handling and cleaning finished-workpieces and of cleaning the machine tools and surrounding Work area are minimized when the apparatus of thisinvention is used. Whilethe preferred embodiments of the present invention have been shown and described herein, it is obvious that many structural details may be changed without departing from the spirit and scope of theappended claims. I I s r The invention is claimed as follows: I

1. A self-contained unit adapted to be mounted in association with a material working machine for cooling an area of contact between a material working element of the machinetand a. work piece, said unit' comaaaasee prising means defining a mixing chamber for atomized liquid coolant and air under pressure, first supply means including a first conduit for delivering air under pressure to said mixing chamber, second supply means including a reservoir and a second conduit having a restricted orifice for delivering liquid coolant to said mixing chamber in atomized form, a third conduit connected to said mixing chamber and serving as a discharge from said mixing chamber and having an elongated portion having transverse dimension less than the trm'isverse dimension of said mixing chamber for directing the streaming suspension of said atomized coolant in air under pressure formed in said mixing chamber against said area of contact, said third conduit having a restricted discharge orifice whereby said suspension of atomized coolant in air is suddenly expanded immediately before impingement against said area of contact, said first supply means comprising a first distributor member having an inlet passageway and a plurality of outlet ports, said first supply means also comprising an air conduit for each inlet port, said second supply means comprising a second distributor member connected with and supported by said first distributor member and also connected with and supporting said reservoir and having an inlet passageway and a plurality of outlet ports, said second supply means also comprising a coolant conduit having a restricted orifice for each of its outlet ports, and said unit comprising a mixing chamber and a mixing chamber discharge conduit for each pair of air and coolant conduits.

2. A self-contained unit adapted to be mounted in association with a material working machine for cooling an area of contact between a work piece and a material working element of the machine, said unit comprising means defining a mixing chamber for atomized liquid coolant and air under pressure, first supply means including a first conduit for delivering air under pressure to said mixing chamber, second supply means including a reservoir and a second conduit having a restricted e is orifice for delivering liquid coolant to said mixing chamber in atomized form, and a third conduit serving as a discharge from said mixing chamber and having a transverse dimension less than the transverse dimension of said mixing chamber for directing the streaming suspension of said atomized coolant in air under pressure in the mixing chamber against the said area of contact, said third conduit having a restricted discharge orifice whereby said suspension of atomized coolant in air is suddenly expanded immediately before impingement against said area of contact, said first supply means comprising a valve in said first conduit, means actuated by the starting and stopping of said machine, respectively, to open and close said valve and means for normally preventing flow of liquid coolant into said mixing chamber, said last mentioned means being responsive to air under pressure flowing through said valve to permit flow of liquid coolant into said mixing chamber.

References Cited in the tile of this patent UNITED STATES PATENTS 1,036,173 Arey Oct. 20, 1912 1,630,835 Doyle May 31, 1927 1,809,999 Wier June 16, 1931 1,930,035 Bogart Oct. 10, 1933 2,230,609 Cannon Feb. 4, 1941 2,252,200 Plummer Aug. 12, 1941 2,377,146 Hadley May 29, 1945 2,471,727 Creamer May 31, 1949 2,507,437 Eserkaln May 9, 1950 2,559,544 Paasche July 3, 1951 2,577,437 Stringer Dec. 4, 1951 2,645,528 Thorsen July 14, 1953 2,653,517 Pigott Sept. 29, 1953 2,676,847 Kelley Apr. 27, l 54 2,678,236 Tinker May 11, 1954 2,764,455 Seibel Sept. 25, 1956 UNITED STATES PATENT OFFICE CERTIFICATE GE CORRECTIUN 7 Patent N0c 2,929 Q5366 March 22, 1960 Jens As. Paasche It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

after may' insert not line 51 1' 49, Column 7 2 inc column 8 line l2 for "corespcmiling read corresponding after "upon" insert by -e Signed and sealed this 30th day of August 1960 (SEAL) Attest:

ERNEST W, SWIDER ROBERT C. WATSON Attesting Oflicer Commissioner of Patents 

